Analysis for atrial fibrillation waves

The major atrial frequencies (MAFs) and their corresponding major atrial cycle lengths (MACLs) were evaluated by analysing spectra of atrial fibrillation waves (AFW) from a patient with atrial fibrillation (AF). The running variations of MAF were studied. The electrocardiosignal (ECS) was acquired at sampling rate 512 Hz, in 20 seconds. After ECS was smoothed and QRST complex subtracted, the remainder is the AFW signal. Then its windowed FFT with 1024 points was computed. The spectral distribution in whole band, major band ranged 3 to 13 Hz, and running spectra in whole band, 3 to 33 Hz band and >33 Hz band were given. MAFs and corresponding MACLs from 4 to 12 Hz, power values in whole band, major band ranged 4 to 12 Hz, ⩽20 Hz band, ⩽30 Hz band and ⩾4 Hz band were computed, respectively. The results showed that (1) the major power value of AFW were in lower than 20 Hz band (e.g. 99.5%). (2) there is a spectral distribution in the band ranged 4 to 12 Hz. The 1st, 2nd and 3rd peak frequencies taken by power order were named MAF1, MAF2 and MAF3, respectively. The MAF1 was called as the dominant atrial frequency (DFA), its corresponding atrial cycle length was called as the dominant atrial cycle length (DACL). The latter was related to the atrial functional refractory period (AFRP) strictly. (3) The complexity of the spectral distribution in 4 to 12 Hz band suggests the complexity of AFW in time domain. (4) The dynamic spectral analysis showed that the DAF is unstable over time. Any significant structure in >30 Hz band was not observed